1. Field of the Invention
The present invention is directed to the field of transistors. In particular, the present invention is directed to the field of vertical charge ordered transistors.
2. Description of the Related Technology
Complex oxide heterostructures have been identified as a potential material platform for the development of novel electronic devices based on properties present in oxides but absent in conventional semiconductors such as metal-insulator transitions, correlated electronic phenomena, and ferroelectricity. A central challenge, and promise, to the growing field of oxide electronics lies not in the reproduction of traditional semiconductor devices with new materials, but rather in the development of novel devices with different operational mechanisms and utilities. Examples of such devices include field effect transistors (FETs) with ferroelectric gate oxides, modulation-doped Mott FETs, and nanoscale FETs that can be written and erased with scanning probe techniques.
Charge ordering, exhibited by a variety of complex oxides, holds promise as the physical basis for electronics as the charge ordering transition is accommodated by an abrupt increase in resistivity, occurs at ultrafast time scales, opens up a gap in the density of states, and can be manipulated with relatively small magnetic and electric fields. Additionally, charge ordering is often only stable in narrow compositional windows that correspond to specific carrier concentrations, such as 0.5 or 0.33 free electrons or holes per unit cell.
In compounds with narrow phase stability or in materials near the vicinity of a charge ordered to metallic transition, one may expect the application of a gate bias that accumulates or depletes a large concentration of carriers to destabilize the charge ordered phase, triggering an electric-field controllable insulator-to-metal transition. Previous work has demonstrated gate bias-induced carrier modulations in complex oxide systems, including materials in the charge ordered phase.
Therefore there is a need in the field to effectively charge order material for forming transistors, and in particular vertical charge ordered transistors.